have been a popular food for the aquarium trade almost since its inception, and gathering them from open sewers for this purpose was quite common until recently. Most are now commercially obtained from the effluent of fish hatcheries, or from professional worm farms. Using these worms as a live food has come with certain problems over the years. When harvested from sewers, open bodies of water, and even from hatcheries, they may be infected with various diseases. This risk can be partially solved by keeping the worms under brisk running water until they have voided the contents of their digestive systems. However, the worms can still be vectors for whirling disease, which can affect salmonids. Additionally, they are very difficult for some fish to obtain in the wild, so certain fish, such as Rift Valley cichlids, will obsessively consume them until they make themselves sick. Additionally, while the worms have good-quality proteins, they also are very fattening, and are poor in certain important amino acids. Fish fed on them can grow rapidly, but may be less healthy and colorful than fish with more balanced diets. Lastly, in poorly cleaned aquaria, Tubifex can become established as a pest species, covering the bottom of the aquarium in a thick carpet which may be considered unsightly. Tubifex in sewers In 2009, a large blobby mass made of colonies of Tubifex was found to be living in the sewers of Raleigh, North Carolina. Revealed by a snake camera inspection of sewer piping under the Cameron Village shopping center, videos of the "creature" went viral on YouTube in 2009 under the name "Carolina poop monster". Tubifex species The genus includes the following species: Tubifex blanchardi (Vejdovský, 1891) Tubifex harmani Loden, 1979 Tubifex costatus (Claparède, 1863) Tubifex ignotus (Stolc, 1886) Tubifex kryptus Bülow, 1957 Tubifex longipenis (Brinkhurst, 1965) Tubifex montanus Kowalewski, 1919 Tubifex nerthus Michaelsen, 1908 Tubifex newaensis (Michaelsen, 1903) Tubifex newfei Pickavance & Cook, 1971 Tubifex pescei (Dumnicka 1981) Tubifex pomoricus Timm, 1978 Tubifex pseudogaster (Dahl, 1960) Tubifex smirnowi Lastockin, 1927 Tubifex superiorensis Brinkhurst & Cook, 1971 Tubifex tubifex (O. F. Müller , 1774) References Tubificina it:Tubifex pl:Rureczniki